A monkey is swinging from a tree. On the first swing, she passes through an arc whose length is 24 m. With each swing, she travels along an arc that is half as long as the arc of the previous swing. Which expression gives the total length the monkey swings in her first n swings?
a. 24. (1-1.5ⁿ)/-0.5
b. 24. (1-1.5ⁿ)/0.5
c. 24. (1-0.5ⁿ)/-0.5